Contamination of meat and meat products with various pathogens such as species of Listeria, Escherichia, Salmonella, Campylobacter, and others, is a problem that has existed for many years. While various other microbiocidal materials have been investigated for efficacy, antimicrobial substances typically used in actual practice in animal processing in slaughterhouses have been certain acids or certain chlorine-based biocidal agents such as sodium hypochlorite and calcium hypochlorite.
Huge numbers of four-legged animals are slaughtered and processed for meat and meat products consumed either by humans or pets. Such animals include, for example, cattle, swine, horses, sheep, bison, rabbit, camel, kangaroo, alligator, crocodile, and other such existing or potential sources of meat products, such as buffalo, goats, and llamas. These and other four-legged meat-producing animals used for food and food products, e.g., deer, antelope, elk, squirrel, opossum, racoon, and nutria, are sometimes referred to collectively herein as four-legged slaughter animals. Also the term “cattle” is used in a generic sense to include steers, heifers, cows, calves, and bulls; “swine” is used in a generic sense to include hogs, sows, gilts, barrows, boars, and pigs; and the term “sheep” is used in a generic sense to include lambs, rams and ewes.
Many four-legged slaughter animals, especially those from which beef or pork are obtained, are processed by high-output meat packing plants using state-of-the-art technology. Despite modern processing procedures, bacterial contamination of fresh meat occurs as an undesirable but unavoidable result of converting live four-legged slaughter animals into food. Although current Good Manufacturing Procedures (GMPs) and/or recent government regulations can reduce this contamination, the total elimination of bacteria from fresh raw meats has not been achieved. Since deep muscle tissue is considered sterile in healthy animals, essentially all of the contamination originates from the carcass surfaces. Soil, dust and manure on the hair, hides and hooves of the animals represent one significant source of contamination. In addition, in some cases internal organs rupture during the removal process, resulting in further contamination of the carcass.
The general nature of the procedures and equipment used in the processing of four-legged slaughter animals for food is well-known to those of ordinary skill in the art. Indeed the literature in the field is extensive. For example, Outlines by G. R. Acuff, PhD, Professor of Food Microbiology, Texas A & M University, of a Pathogen Reduction Dialogue held May 6, 2002, describes a typical cattle slaughter operation as involving the following steps: Cattle Receiving & Holding, Stunning, Exsanguination, Head and Shank Removal, Hide Removal, Evisceration, Carcass Splitting, Final Wash, and Chill. For hog slaughter, Dr. Acuff, id., identifies the following steps: Hog Receiving & Holding, Stunning, Exsanguination, Scalding, Dehairing, Singeing, Scraping & Polishing, Evisceration, and Wash & Chill. Other authors give descriptions which are along the same general lines but which may vary to some extent. For example, slaughtering and processing of cattle as described in a chapter entitled Overview of Meat Processing refers in part to and explains the following processing steps: Pre-handling of cattle, Stunning and bleeding, Dressing and hide removal, Evisceration, and Cutting and boning. In addition, the chapter further explains that carcass cutting and boning often take place after chilling to but that recent developments have made it possible to undertake boning while the carcass is still warm, a method referred to as “hot boning”. The same chapter describes and explains the steps in slaughtering and processing of pigs as including: Pre-handling of pigs, Stunning and bleeding, Dehairing and finishing, and Evisceration and splitting, with a statement in this latter section that, finally, the carcasses are chilled rapidly overnight before the subsequent processes of cutting and boning. Thus anyone unfamiliar with the steps or operations involved in the processing of four-legged slaughter animals for food can obtain a vast amount of information by reference to the extensive literature on the subject.
A number of the conventionally-used steps in the processing of four-legged slaughter animals for food constitute opportunities for microbial and pathogen contamination. A need thus exists for one or more new methods for reducing or eliminating such contamination of animal carcasses or parts thereof during the processing of four-legged slaughter animals for food. Another need is for the provision of one or more methods which do not involve excessive expense in reducing or eliminating such contamination. A further need is for the provision of one or more methods which do not involve undue interference with existing slaughterhouse and/or meat packing operations.
Besides fulfilling the foregoing needs, it is vitally important that the method used to fulfill the foregoing needs not cause any noticeable degradation in the quality or properties of the meat from the carcasses, especially in the appearance and taste of the meat.
This invention is deemed to enable fulfillment of the foregoing needs, and to cause no noticeable degradation in the quality or properties of the meat from the carcasses resulting from the use or the methods of this invention.